Choshen, the breastplate, first worn by the High Priest Aaron, and subsequently worn by every High Priest in the Temple while performing holy duties. There were 12 precious stones in the Hoshen, as mentioned in Book of Exodus: Ruby, Garnet, Citrine, Blue Topaz, Topaz, Sapphire, Peridot, Onyx, Emerald, Diamond, Amethyst, Aquamarine. Various Jewish sources teach us that in addition to representing the Twelve Tribes of Israel, each stone has served as an expression of faith and optimism throughout the generations.